Robot apparatus

ABSTRACT

The present invention provides a robot apparatus which can determine a contact state at a contact point without increasing the contact point, can be miniaturized, and also can decrease the cost. Contact points are provided in a hand device. Contact points are provided in a tool device, which come in contact with the contact points, respectively, when the tool device has been mounted on the hand device. A voltage detecting circuit is provided in the tool device, which detects a voltage between the contact points. The controlling circuit determines contact states between the contact points and the contact points, by using a value of the voltage which has been detected by the voltage detecting circuit.

This application is a division of application Ser. No. 15/044,834, filedFeb. 16, 2016.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a robot apparatus in which a tooldevice is mounted on a hand device.

Description of the Related Art

Currently, a robot is applied to a manufacturing apparatus in a factory,and parts are transferred and/or assembled with the use of the robot.This type of robot is structured so as to have an electrically-operatedrobot hand (hand) attached to the head of a robot arm (arm) of amulti-axis and a multi-joint, or of a linearly moving arm.

One robot is needed to perform a plurality of operations for a limitedproduction of a wide variety of products, and as a method therefor, therobot is occasionally made to grip in a hand an electrically-operatedtool which can perform the operation that is hard to be performed by thehand, and makes the electrically-operated tool perform the operation.The tool is, for instance, a pincette tool which performs the transferor the assembly for a small work or a thin work, or an absorbing chucktool which absorbs and acquires a work.

An electric power can be supplied to and a signal can be a transmittedto the tool, if a contact point of the hand is electrically connectedwith a contact point of the tool when the hand grips the tool. The toolcan be driven by the electric power and the signal which are thussupplied from the hand.

However, there has been a case where the sufficient electric powercannot be supplied and the signal cannot be transmitted because acontact resistance increases and a voltage drop becomes large in theconnection portion between the contact point of the hand and the contactpoint of the tool, due to a contact failure, an aged deterioration andthe like.

On the other hand, in order to avoid a stop of the apparatus due to thecontact failure and the aged deterioration in the connection portionbetween the contact points, a method is proposed which detects thecontact resistance between the contact points (Japanese PatentApplication Laid-Open No. 2007-298288).

In the method disclosed in Japanese Patent Application Laid-Open No.2007-298288, in order to measure the contact resistance between thecontact point on a main body side and the contact point on a load side,a reference resistance is connected in series to the contact point onthe main body side; the contact point for measurement is provided on themain body side and the contact point for measurement is provided on theload side, respectively; and the contact point and the contact point forthe measurement are short-circuited on the load side. Then, a detectingunit arranged on the main body side detects a potential differenceoccurring in the reference resistance, and a potential differenceoccurring in a series circuit of the contact point in the main bodyside, the contact point in the load side, the contact point for themeasurement in the load side and the contact point in the main bodyside; and grasps the contact resistance based on those detectionresults.

It is also considered to apply the configuration of Japanese PatentApplication Laid-Open No. 2007-298288 to the robot apparatus having thehand and the tool, but the hand and the tool have each a plurality ofcontact points, and accordingly it has been necessary to increase thecontact point for the measurement for each of the contact points,respectively. Then, there is a necessity of increasing the number of thecontact points. Accordingly, the hand and the tool have been upsized andalso the number of parts have increased, which have consequently causedincrease in the cost.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a robot apparatus whichcan determine a contact state at a contact point without increasing thecontact point, to miniaturize the robot apparatus, and also to decreasethe cost.

According to an aspect of the present invention, a robot apparatuscomprises: a hand device; a hand side contact point which is provided inthe hand device and to which a voltage is applied; a tool device whichcan be attached to and detached from the hand device; a tool sidecontact point which is provided in the tool device, and comes in contactwith the hand side contact point as the tool device is mounted on thehand device; a tool side voltage detecting unit which is provided in thetool device, and detects a voltage of the tool side contact point; and acontrolling unit which determines a contact state between the hand sidecontact point and the tool side contact point, by using a value of thevoltage that has been detected by the tool side voltage detecting unit.

According to the present invention, the robot apparatus can determinethe contact state at the contact point without increasing the number ofthe contact points, can be miniaturized, and can decrease the cost.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory view illustrating a robot apparatus accordingto a first embodiment.

FIG. 2 is a block diagram illustrating an integrated controllingapparatus, a hand and a tool of the robot apparatus according to thefirst embodiment.

FIG. 3 is a flow chart which is used when a contact state of a contactpoint is determined, in the robot apparatus according to the firstembodiment.

FIG. 4 is a schematic diagram illustrating a relation between an elapsedtime and a difference value between voltages, in the first embodiment.

FIG. 5 is a flow chart illustrating the time at which the tool isreleased, in the robot apparatus according to the first embodiment.

FIG. 6 is a block diagram illustrating an integrated controllingapparatus, a hand and a tool of a robot apparatus according to a secondembodiment.

FIG. 7 is a flow chart which is used when a contact state of a contactpoint is determined, in the robot apparatus according to the secondembodiment.

FIG. 8 is a schematic diagram illustrating a relation between an elapsedtime and a value of a contact resistance, in the second embodiment.

FIG. 9A is a graph illustrating a relation between the number of toolacquiring times by the hand and a value of the contact resistance, inthe second embodiment. FIG. 9B is a graph in which a part of sections inFIG. 9A is expanded.

FIG. 10 is a graph illustrating experimental values of a current valueof a power source, at the time when a tool stops and at the time afterthe tool has completed gripping a work, in a third embodiment.

FIG. 11 is a block diagram illustrating an integrated controllingapparatus, a hand and a tool of a robot apparatus according to a fourthembodiment.

FIG. 12 is an explanatory view illustrating a robot apparatus accordingto a fifth embodiment.

DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawings.

First Embodiment

FIG. 1 is an explanatory view illustrating a robot apparatus accordingto a first embodiment of the present invention. The robot apparatus 10includes: a robot 200 having a robot arm (hereafter referred to as“arm”) 300 and a robot hand (hereafter referred to as “hand”) 400; atool 500 which is attachable to and detachable from the hand 400; and anintegrated controlling apparatus 100 which integrally controls these.

The arm 300 is an electrically-operated robot arm. The arm 300 is avertical multi-joint robot arm, and is a robot arm which has six joints,specifically, a robot arm which has six axes. A proximal end 301 of thearm 300 is fixed to a trestle 900, and a head 302 of the arm 300 is afree end. The hand 400 is attached to the head 302 of the arm 300. Aposition and an orientation of the hand 400 can be changed by a rotationor a swing of each joint of the arm 300.

A tool storage site 600 which supports the tool 500 thereon that hasbeen removed from the hand 400 is mounted on the trestle 900.

The hand 400 is an electrically-operated robot hand. The hand 400includes: a hand device 410; a hand side contact unit 420 which has aplurality of contact points; and a control board 430 for controlling thehand device 410.

The hand device 410 includes: a base unit 401; a plurality of claws 402which are supported by the base unit 401; and an electric motor(hereafter referred to as “motor”) 403 which drives the plurality ofclaws 402 in an opening and closing direction (in radial direction withrespect to base plane of base unit 401). The number of the claws 402 isset at two in the present embodiment, but the number is not limited totwo, and may be three or more. When the opening and the closing of theplurality of claws 402 are driven, the plurality of claws 402 is enabledto grip or release the grip of the work or the tool 500.

The hand side contact unit 420 is provided in the hand device 410,specifically, in the base unit 401. A motor 403 is, for instance, aservo motor such as a brushless DC motor. The motor 403 and the controlboard 430 are provided in the inside of the base unit 401.

The tool 500 is the electrically-operated tool. The tool 500 includes: atool device 510, a tool side contact unit 520 having a plurality ofcontact points; and a control board 530 for controlling the tool device510.

The tool device 510 includes: a base unit 501; a plurality of claws 502which are supported by the base unit 501; and an electric motor(hereafter referred to as “motor”) 503 which drives the plurality ofclaws 502 in an opening and closing direction (in radial direction withrespect to base plane of base unit 501). The number of the claws 502 isset at two in the present embodiment, but the number is not limited totwo, and may be three or more. When the opening and the closing of theplurality of claws 502 are driven, the plurality of claws 502 is enabledto grip or release the grip of the work.

The tool side contact unit 520 is provided in the tool device 510,specifically, in the base unit 501. The motor 503 is, for instance, aservo motor such as a brushless DC motor. The motor 503 and the controlboard 530 are provided in the inside of the base unit 501.

The hand 400 (hand device 410) grips or releases the grip of the tool500 (tool device 510), and thereby the tool 500 (tool device 510)results in being attached to and detached from the hand 400 (hand device410). In other words, the tool device 510 is structured so as to beattachable to and detachable from the hand device 410.

The integrated controlling apparatus 100 and the arm 300 are connectedby an arm wiring 201. The integrated controlling apparatus 100 controlseach axis of the arm 300, by supplying an electric power and a signal tothe arm 300 through the arm wiring 201.

The integrated controlling apparatus 100 and the hand 400 are connectedby a hand wiring 202 which is arranged in the inside of the arm 300. Theintegrated controlling apparatus 100 controls the opening and closing ofthe claws 402 of the hand 400, by supplying the electric power and thesignal to the hand 400 through the hand wiring 202.

The integrated controlling apparatus 100 moves the arm 300, and makesthe hand 400 grip the tool 500 which is placed on the tool storage site600. Thereby each contact point of the hand side contact unit 420 andeach contact point of the tool side contact unit 520 come in contactwith each other. The integrated controlling apparatus 100 controls theopening and closing of the claws 502 of the tool 500, by supplying theelectric power and the signal to the tool 500 through the hand 400 (handwiring 202).

The tool 500 has a role of performing an operation which is difficultfor the hand 400. The tool is, for instance, the pincette tool whichperforms the transfer or the assembly of a small work or a thin work,and the absorbing chuck tool which absorbs and acquires the work. In thefirst embodiment, the case will be described where the tool 500 is thepincette tool.

FIG. 2 is a block diagram illustrating the integrated controllingapparatus, the hand and the tool of the robot apparatus according to thefirst embodiment of the present invention. In FIG. 2, a state isillustrated in which the tool 500 (tool device 510) has been mounted onthe hand 400 (hand device 410), specifically, a state in which the tool500 is gripped by the hand 400.

The integrated controlling apparatus 100 includes: a controlling circuit101 which integrally controls the whole robot apparatus as a controllingunit; a memory 102 which stores various data (information) therein, as amemory unit; and a power source circuit 103 for supplying an electricpower to the whole robot apparatus therefrom, as a power source unit.The integrated controlling apparatus 100 also includes: a monitor 104which displays an image thereon according to instructions of thecontrolling circuit 101, as an annunciation unit; and a counter 105which counts the number of times the tool device 510 has been mounted onthe hand device 410.

In response to an input, for instance, of a commercial power source, thepower source circuit 103 outputs a fixed direct-current voltage (forinstance, 24 [V]). Incidentally, the case will be described below wherethe power source unit is the power source circuit 103, but the powersource unit may be a battery.

The control board 430 (refer to FIG. 1) of the hand 400 includes: a handcontrolling apparatus 431 which is a hand controlling unit; a voltagedrop circuit 432; a power switch circuit 433; a motor driver circuit434; a voltage detecting circuit 435; a signal switch circuit 436; and adischarge circuit 437, which are illustrated in FIG. 2. The controlboard 530 (refer to FIG. 1) of the tool 500 includes: a tool controllingapparatus 531 which is a tool controlling unit; a voltage drop circuit532; a motor driver circuit 534; and a voltage detecting circuit 535,which are illustrated in FIG. 2.

The hand side contact unit 420 has a plurality of contact points 421 to424 (four in first embodiment). The tool side contact unit 520 has aplurality of contact points 521 to 524 (four in first embodiment). Eachof the contact points 421 to 424 comes in contact with each of thecorresponding contact points 521 to 524, when the tool device 510 hasbeen mounted on the hand device 410. Thereby, continuity is formedbetween each of the contact points 421 to 424 and each of the contactpoint 521 to 524.

The power source circuit 103 of the integrated controlling apparatus 100and the voltage drop circuit 432 of the hand 400 are connected by twopower source wires. In addition, the power source circuit 103 and thecontact points (hand side contact point) 423 and 424 of the hand sidecontact unit 420 are connected by two power source wires 443 and 444through the power switch circuit 433. In other words, the power sourcewires 443 and 444 are electrically connected to the contact points 423and 424 of the hand side contact unit 420, respectively.

The controlling circuit 101 and the hand controlling apparatus 431 ofthe integrated controlling apparatus 100 are connected by two signalwires. Thereby, the controlling circuit 101 and the hand controllingapparatus 431 can mutually send and receive signals (communicate)through the signal wires.

The hand controlling apparatus 431 and the contact points (hand sidesignal contact point) 441 and 442 of the hand side contact unit 420 areconnected by two signal wires 441 and 442 through the signal switchcircuit 436. In other words, the signal wires 441 and 442 areelectrically connected to the contact points 421 and 422 of the handside contact unit 420, respectively.

The contact points (tool side contact point) 523 and 524 of the toolside contact unit 520 and the voltage drop circuit 532 are connected bytwo power source wires 543 and 544. In other words, the power sourcewires 543 and 544 are electrically connected to the contact points 523and 524 of the tool side contact unit 520, respectively.

In addition, the contact points (tool side signal contact points) 521and 522 of the tool side contact unit 520 and the tool controllingapparatus 531 are connected by two signal wires 541 and 542. As for thedetailed description, the signal wires 541 and 542 are electricallyconnected to the contact points 521 and 522 of the tool side contactunit 520, respectively.

In the first embodiment, a power source potential (for instance, +24[V]) is applied to one of the two power source wires, and a groundpotential (for instance, 0 [V]) is applied to the other power sourcewire. In addition, two signals are supplied to two signal wires. One ofthe two signals, which will become a positive side (+), is supplied toone signal wire of the two signal wires, and the other signal which willbecome the negative side (−) is supplied to the other signal wire. Thedifference between the two signals becomes a differential signal.

The voltage drop circuit 432 of the hand 400 drops a direct-currentvoltage applied by the power source circuit 103 to a control voltagewhich is used for an operation of the hand controlling apparatus 431,and applies the control voltage to the hand controlling apparatus 431.In addition, the voltage drop circuit 432 drops a direct-current voltageapplied by the power source circuit 103 to a motor voltage which is usedfor an operation of the motor driver circuit 434, and applies the motorvoltage to the motor driver circuit 434.

The hand controlling apparatus 431 controls an operation of the handdevice 410, specifically, of the claws 402 (or motor 403), in responseto an input of an operation signal sent from the controlling circuit101.

Specifically, the hand controlling apparatus 431 which has received theinput of operation signal outputs a control signal to the motor drivercircuit 434 to control the motor driver circuit 434. The motor drivercircuit 434 modulates the pulse width of the motor voltage applied bythe voltage drop circuit 432 according to the control signal, andapplies the modulated voltage to the motor 403. Thus, the power sourcecircuit 103 supplies an electric power which is necessary for therotation of the motor 403, to the motor 403, and the hand controllingapparatus 431 controls the rotation of the motor 403. The motor 403 isconnected to the claws 402, and the claws 402 open and close accordingto the rotation of the motor 403.

An encoder (unillustrated) is connected to the motor 403, which enablesa positional control, and a speed control based on a difference valuebetween the positions. In addition, a motor current detecting circuit(unillustrated) which detects a current value of the motor 403 isprovided in the hand device 410, and enables the current control of themotor 403.

The hand controlling apparatus 431 outputs the control signal to thepower switch circuit 433, and controls ON and OFF of the power switchcircuit 433. Specifically, the power switch circuit 433 controls thesupply/non-supply of the electric power to the contact points 423 and424, in other words, the supply/non-supply of the electric power to thetool 500, according to the control signal.

The hand controlling apparatus 431 outputs a control signal to thesignal switch circuit 436, and controls ON and OFF of the signal switchcircuit 436. Specifically, the signal switch circuit 436 controls thesupply/non-supply of the signal to the contact points 421 and 422, inother words, the supply/non-supply of the signal to the tool 500,according to the control signal.

When operating the hand 400 (hand device 410), the hand controllingapparatus 431 controls both of the power switch circuit 433 and thesignal switch circuit 436 to turn the switches OFF, and intercepts theelectric power and the signal being supplied to the tool 500.

Thereby, the hand controlling apparatus 431 operates the motor drivercircuit 434, according to an operation signal which has been input fromthe controlling circuit 101 and the hand controlling apparatus 431 hasreceived, and controls the rotation of the motor 403. Thereby, the handcontrolling apparatus 431 controls an operation of the hand device 410(claws 402).

When the hand 400 has gripped the tool 500, in other words, when thetool device 510 has been mounted on the hand device 410, each of thecontact points 421 to 424 of the hand side contact unit 420 comes incontact with each of the contact points 521 to 524 of the tool sidecontact unit 520. After that, the power switch circuit 433 is turned ONby the hand controlling apparatus 431, and an electric power is suppliedto the voltage drop circuit 532 of the tool 500.

A direct-current voltage is applied to the voltage drop circuit 532 bythe power source circuit 103, through the power source wires 443 and444, the contact points 423 and 424, the contact points 523 and 524, andthe power source wires 543 and 544. The voltage drop circuit 532 dropsthe direct-current voltage which has been applied by the power sourcecircuit 103 to a control voltage which is used for an operation of thetool controlling apparatus 531, and applies the control voltage to thetool controlling apparatus 531.

In addition, the voltage drop circuit 532 drops a direct-current voltageapplied by the power source circuit 103 to a motor voltage which is usedfor an operation of the motor driver circuit 534, and applies the motorvoltage to the motor driver circuit 534.

The hand controlling apparatus 431 controls the signal switch circuit436 to turn the switch ON, after the electric power has been supplied.Thereby, the hand controlling apparatus 431 and the tool controllingapparatus 531 are enabled to mutually send and receive signals(communicate). The tool controlling apparatus 531 controls an operationof the tool device 510, specifically, the claws 502 (specifically motor503), in response to the input of an operation signal sent from thecontrolling circuit 101 through the hand controlling apparatus 431.

Specifically, the tool controlling apparatus 531 which has received theinput of operation signal outputs a control signal to the motor drivercircuit 534 to control the motor driver circuit 534. The motor drivercircuit 534 modulates the pulse width of the motor voltage applied bythe voltage drop circuit 532 according to the control signal, andapplies the modulated voltage to the motor 503. Thus, the power sourcecircuit 103 supplies an electric power which is necessary for therotation of the motor 503, to the motor 503, and the tool controllingapparatus 531 controls the rotation of the motor 503. The motor 503 isconnected to the claws 502, and the claws 502 open and close accordingto the rotation of the motor 503.

Here, suppose that the electric power is always supplied to the contactpoints 423 and 424 in the hand side contact unit 420. When the contactpoints 423 and 424 come in contact with the contact points 523 and 524in the tool side contact unit 520, a deterioration phenomenon such as anarc discharge occurs in the contact points. Similarly, suppose that thesignals are always supplied to the contact points 421 and 422 in thehand side contact unit 420. When the contact points 421 and 422 come incontact with the contact points 521 and 522 in the tool side contactunit 520, the deterioration phenomenon such as the arc discharge occursin the contact points.

In contrast to this, in the first embodiment, the hand 400 has the powerswitch circuit 433 and the signal switch circuit 436. When the hand 400grips the tool 500, in other words, when the tool device 510 is mountedon the hand device 410, each of the switching circuits 433 and 436 areturned OFF. Thereby, the deterioration of each of the contact points ineach of the contact units 420 and 520 can be suppressed. In addition,such a phenomenon can be prevented that when a work, a jig or the likehas come in contact with the hand side contact unit 420, an electriccurrent flows to the work or the jig.

An encoder (unillustrated) is connected to the motor 503, which enablesa positional control, and a speed control based on a difference valuebetween the positions. In addition, a motor current detecting circuit(unillustrated) which detects a current value of the motor 503 isprovided in the tool device 510, and enables the current control of themotor 503.

The voltage detecting circuit 435 which is the hand side voltagedetecting unit is provided in the hand device 410, and the voltagedetecting circuit 535 which is the tool side voltage detecting unit isprovided in the tool device 510.

The degree of deterioration with the passage of time of each of thecontact points in each of the contact units 420 and 520 is almost thesame as the others, and accordingly in the first embodiment, a contactstate between the contact points 423 and 424 in the hand side contactunit 420 and the contact points 523 and 524 in the tool side contactunit 520 are determined.

Because of this, in the first embodiment, the voltage detecting circuit435 detects voltage (potential difference) between the two contactpoints 423 and 424. Specifically, the voltage detecting circuit 435detects the voltage between an arbitrary point (detecting point) of thepower source wire 443 and an arbitrary point (detecting point) of thepower source wire 444. Each of the detecting points is preferably closeto each of the contact points 423 and 424, in consideration of also thevoltage drop due to wiring resistance in each of the power source wires443 and 444. In the first embodiment, the contact point 423 becomes apower source potential, and the contact point 424 becomes a groundpotential; and accordingly, the voltage detecting circuit 435 detectsthe voltage of the contact point 423 relative to the contact point 424.

The voltage information (signal which shows value of voltage) which hasbeen detected by the voltage detecting circuit 435 is output to thecontrolling circuit 101 of the integrated controlling apparatus 100,through the hand controlling apparatus 431.

The voltage detecting circuit 535 detects voltage (potential difference)between the two contact points 523 and 524. Specifically, the voltagedetecting circuit 535 detects the voltage between an arbitrary point(detecting point) of the power source wire 543 and an arbitrary point(detecting point) of the power source wire 544. Each of the detectingpoints is preferably close to each of the contact points 523 and 524, inconsideration of also the voltage drop due to wiring resistances in eachof the power source wires 543 and 544. In the first embodiment, thecontact point 523 becomes the power source potential, and the contactpoint 524 becomes the ground potential; and accordingly, the voltagedetecting circuit 535 detects the voltage of the contact point 523relative to the contact point 524.

The voltage information (signal which shows value of voltage) which hasbeen detected by the voltage detecting circuit 535 is output to thecontrolling circuit 101 of the integrated controlling apparatus 100,through the tool controlling apparatus 531, the contact points 521 and522, the contact points 421 and 422, and the hand controlling apparatus431.

Thus, the controlling circuit 101 of the integrated controllingapparatus 100 acquires the value of voltage which has been detected bythe voltage detecting circuit 435, and the value of voltage which hasbeen detected by the voltage detecting circuit 535.

FIG. 3 is a flow chart which is used when the contact state among thecontact points is determined, in the robot apparatus according to thefirst embodiment of the present invention. In FIG. 3, the contact stateamong the contact points is determined at the time of the initializationwhich is performed after the hand 400 has acquired the tool 500.

First, the controlling circuit 101 of the integrated controllingapparatus 100 controls the arm 300 to operate the arm 300 to a positionat which the hand 400 contacts the tool 500 (S11). Thereby, thecontrolling circuit 101 makes the arm 300 move the hand 400, and makesthe hand 400 come in contact with the tool 500.

After that, the controlling circuit 101 makes the hand 400 grip the tool500 (S12). Specifically, the controlling circuit 101 transmits theoperation signal to the hand controlling apparatus 431 of the hand 400so as to move a plurality of claws 402 to such a direction that theclaws 402 are closed. The hand controlling apparatus 431 makes the motor403 rotate according to the operation signal, thereby makes theplurality of claws 402 move to such a direction that the claws 402 areclosed, and makes the hand 400 grip the tool 500.

After the hand 400 has completed gripping, the hand 400 supplies anelectric power to the tool 500 (S13). Specifically, the controllingcircuit 101 transmits such an instruction as to turn the switches ON ofthe power switch circuit 433 and the signal switch circuit 436, to thehand controlling apparatus 431. The hand controlling apparatus 431 whichhas received the instruction sequentially turns the switches ON of thepower switch circuit 433 and the signal switch circuit 436. Thereby, anelectric power is enabled to be supplied from the hand 400 to the tool500, and the hand controlling apparatus 431 and the tool controllingapparatus 531 become a state of being capable of transmitting andreceiving the signal to and from each other.

Next, after the signal switch circuit 436 has been turned ON, it ischecked whether or not the hand controlling apparatus 431 and the toolcontrolling apparatus 531 can exchange signals mutually (check signal)(S14). In other words, it is checked whether or not the hand controllingapparatus 431 and the tool controlling apparatus 531 can communicatewith each other. Specifically, the hand controlling apparatus 431transmits a check signal to the tool controlling apparatus 531, andchecks whether or not having received a response signal to this checksignal from the tool controlling apparatus 531.

In a normal case, there is a reply from the tool controlling apparatus531 to the hand controlling apparatus 431. In a case where there isabnormality, there is no reply from the tool controlling apparatus 531.In other words, if the apparatuses can communicate with each other,there is the reply (response) from the tool controlling apparatus 531,and the tool 500 is initialized (S15). The initialization of the tool500 means a position alignment of the motor 503 with the claws 502, anda prior operation necessary for using the tool 500, such as a Z-phasedetection of the encoder (unillustrated) of the motor 503.

In the case where there is no reply from the tool controlling apparatus531 even though a fixed time period has passed in the signal check inthe step S14, the hand controlling apparatus 431 transmits a signalwhich shows an error, to the controlling circuit 101 of the integratedcontrolling apparatus 100. Then, the controlling circuit 101 which hasreceived the signal which shows the error emits an alert to a user(S21). Specifically, the controlling circuit 101 makes a monitor 104display an image thereon which shows the alert. Incidentally, theannunciation unit which sends the notice to the user is determined to bethe monitor 104, but is not limited to the monitor. The annunciationunit may be an unillustrated loudspeaker, for instance, and may make theloudspeaker output a sound which shows the alert.

The phenomenon that the tool controlling apparatus 531 does not respondoccurs because the hand side contact unit 420 and the tool side contactunit 520 are not connected normally, or because the contacting portionsof the contact points deteriorate and/or catch contaminantstherebetween, and the contact resistance value exceeds a limit value. Byreceiving the alert, the user can maintain the contacting portions.

After the tool 500 has been initialized, the tool 500 is in a state ofbeing capable of being used. Accordingly, the hand controlling apparatus431 transmits a signal which shows that the hand has completed theacquisition of the tool 500, to the controlling circuit 101 of theintegrated controlling apparatus 100 (S16).

The controlling circuit 101 controls the operation of the arm 300 tothereby make the arm 300 move the tool 500 to a work acquisitionposition (S17). The controlling circuit 101 makes the arm 300 operateand thereby move the tool 500 to the work acquisition position.

The controlling circuit 101 transmits an instruction to the toolcontrolling apparatus 531, the tool controlling apparatus 531 controlsthe current flowing in the motor 503, and thereby operates the claws 502until the tool 500 completes gripping the work (S18). As for thecompletion of the gripping operation, a contact sensor (unillustrated)may be provided on the claw 502, and the tool controlling apparatus 531may determine whether or not the gripping operation has been completed,based on the detection result of the contact sensor (unillustrated).Alternatively, the tool controlling apparatus 531 may determine whetheror not the gripping operation has been completed, based on adisplacement between the values of the encoder (unillustrated) of themotor 503.

Next, the controlling circuit 101 of the integrated controllingapparatus 100 acquires the value of the voltage (potential difference)from the voltage detecting circuits 435 and 535 at predeterminedsampling intervals, and determines the contact states between thecontact points 423 and 424 and the contact points 523 and 524 by usingthese detection results (S19).

The time period for sampling data is, for instance, 2 [ms]. It isacceptable to use one data for the determination of the contact state,or it is also acceptable to average a plurality of data (for instance,ten data) and use the average for the determination.

The controlling circuit 101 issues an alert to the user, when havingdetermined that the contact state is NG in the step S19 (S22).Specifically, the controlling circuit 101 makes the monitor 104 displayan image thereon which shows the alert. Incidentally, the annunciationunit which sends the notice to a user is determined to be the monitor104, but is not limited to the monitor. The annunciation unit may be anunillustrated loudspeaker, for instance, and may make the loudspeakeroutput a sound which shows the alert.

When having determined that the contact state is OK in the step S19, orhaving issued the alert in the step S22, the controlling circuit 101makes the robot 200 carry out operations of the transfer of the work,the assembly of the work and the like (S20).

A method for determining the contact state between the contact pointswill be described below in detail. In the first embodiment, the voltagedetecting circuit 435 detects a potential difference between the contactpoints 423 and 424, specifically, a potential difference between a plusside power source potential which has been applied to the contact point423 and a minus side power source potential (ground potential) which hasbeen applied to the contact point 424. In addition, the voltagedetecting circuit 535 detects a potential difference between the contactpoints 523 and 524, specifically, a potential difference between a plusside power source potential which has been applied to the contact point523 and a minus side power source potential (ground potential) which hasbeen applied to the contact point 524.

The tool controlling apparatus 531 does not operate, unless the electricpower and the signal are supplied from the hand controlling apparatus431. Because of this, the controlling apparatus 531 can determine thecontact state of the contact points only when the electric power and thesignal are supplied to the tool 500 side from the hand 400 side.

The controlling circuit 101 acquires the value of the voltage which hasbeen detected by the voltage detecting circuit 435 and the value of thevoltage which has been detected by the voltage detecting circuit 535,and determines the contact states between the contact points 423 and 424and the contact points 523 and 524, by using the detection results.

The above description will be specifically described below. Whendetermining the contact state, the controlling circuit 101 determineswhether or not the difference value between the value of the voltagewhich has been detected by the voltage detecting circuit 435 and thevalue of the voltage which has been detected by the voltage detectingcircuit 535 has exceeded a threshold value (threshold value of voltage)which has been set beforehand. If the difference value exceeds thethreshold value, the contact state is NG, and if the difference valuedoes not exceed the threshold value, the contact state is OK. Here, thethreshold value is a value which is stored beforehand in the memory 102in FIG. 2.

FIG. 4 is a schematic diagram illustrating a relation between an elapsedtime and the difference value between the voltages. As is illustrated inFIG. 4, the contact points in each of the contact units 420 and 520deteriorate with the passage of time if being not maintained, thecontact resistance between the contact points increases, and accordinglythe voltage drop increases which occurs in the connection portionbetween the contact points. Accordingly, the controlling circuit 101determines whether or not such a difference value that the value of thevoltage which has been detected by the voltage detecting circuit 535 hasbeen subtracted from the value of the voltage which has been detected bythe voltage detecting circuit 435 has exceeded the threshold value(threshold value of voltage). Here, in FIG. 4, in addition to thethreshold value, a limit value is illustrated which is larger than thethreshold value. The limit value is a value at which the tool becomesincapable of receiving the electric power or the signal, and thethreshold value is preferably set at a value lower than the limit value.

When the difference value has exceeded the threshold value, thecontrolling circuit 101 only issues the alert for calling such anattention that the user needs to maintain the contact points, forinstance, by cleaning and the like (S22), and does not make the robot200 stop the operation. However, in the case of NG in the step S14, thetool cannot receive the signal, and accordingly the difference valuemust exceed the limit value. Accordingly, the controlling circuit 101issues the alert which shows an error in the step S21, and also makesthe robot 200 stop the operation.

For instance, suppose that the threshold value has been set at 2 [V]. Inthe case where 24 [V], for instance, has been detected by the voltagedetecting circuit 435, and 21 [V], for instance, has been detected bythe voltage detecting circuit 535, the controlling circuit 101calculates a difference value (24 [V]−21 [V]=3 [V]), and determineswhether or not this calculation result has exceeded the threshold value2 [V]. In this case, the difference value exceeds the threshold value (3[V]>2 [V]), and the controlling circuit 101 issues the alert by themonitor 104.

Incidentally, on the contrary, in the case where the voltage value whichhas been detected by the voltage detecting circuit 435 is subtractedfrom the voltage value which has been detected by the voltage detectingcircuit 535, the difference value becomes a minus value and thethreshold value may be set at the value of a minus. Then, thecontrolling circuit 101 may determine whether or not the differencevalue has exceeded the threshold value to a minus direction.

FIG. 5 is a flow chart illustrating the time at which the tool isreleased, in the robot apparatus according to the first embodiment ofthe present invention.

Firstly, the integrated controlling apparatus 100 makes the arm 300operate to make the hand 400 and the tool 500 move to the upside of thetool storage site 600 (S31). After that, the integrated controllingapparatus 100 makes the hand 400 stop supplying the electric power andthe signal from the hand 400 side to the tool 500 side (S32).

At the same time when processing the step S32, the integratedcontrolling apparatus 100 makes the discharge circuit 437 of the hand400 set the potential of the tool 500 at 0 [V] (S33).

By the setting of the potential of the tool 500 at 0 [V], such aphenomenon can be prevented from occurring that the contact pointsdeteriorate due to an arc discharge and the like, when the tool 500leaves from the hand 400. In addition, the potential of the tool 500 canbe more early set at 0 [V] by the discharge circuit 437, and a timeperiod to be spent before the tool 500 is released can be shortened.

After the step S33, the hand 400 releases the tool 500 (S34), and thetool controlling apparatus 531 transmits a signal which shows that anoperation of releasing the tool has been completed, to the integratedcontrolling apparatus 100 (S35).

As has been described above, the robot apparatus according to the firstembodiment determines the contact states between the contact points 423and 424 and the contact points 523 and 524, by using the value of thevoltage which has been detected by the voltage detecting circuit 535that has been provided in the tool device 510, and accordingly does notneed to increase the number of contact points for the voltage detection.Accordingly, the robot apparatus can miniaturize the hand side contactunit 420 and the tool side contact unit 520, accordingly can miniaturizethe hand 400 and the tool 500, does not need to add the contact pointfor the voltage detection, and accordingly can reduce the cost of thehand 400 and the tool 500.

In addition, the robot apparatus according to the first embodimenttransmits the data (signal) which shows the value of the voltage thathas been detected by the voltage detecting circuit 535, to thecontrolling circuit 101, through the transmission path of the operationsignal which operates the tool device 510, specifically through thecontact points 521 and 522 and the contact points 421 and 422.Accordingly, the robot apparatus does not need to add a contact pointfor transmitting a signal which shows the voltage value that has beendetected by the voltage detecting circuit 535. Therefore, the robotapparatus can miniaturize the hand side contact unit 420 and the toolside contact unit 520, accordingly can miniaturize the hand 400 and thetool 500, does not need to add the contact point for the voltagedetection, and accordingly can reduce the cost of the hand 400 and thetool 500.

In the first embodiment, the integrated controlling apparatus 100 hasthe counter 105 (FIG. 2) which counts the number of times the hand 400has acquired the tool 500, specifically, the number of times the tooldevice 510 has been mounted on the hand device 410. The counted value bythe counter 105 is reset when a user has performed maintenance.

A threshold value (threshold value for count) is set beforehand so thatthe controlling circuit 101 distinguishes whether or not thedeterioration of the contact point can be restored by the maintenance.In other words, the threshold value for the count is stored in thememory 102 beforehand. The controlling circuit 101 determines whether ornot the counted value by the counter 105 at the time when the differencevalue has exceeded the threshold value is smaller than the thresholdvalue for the count. Then, when having determined that the counted valueis smaller than the threshold value for the count, the controllingcircuit 101 makes the monitor 104 display the image showing the noticethereon. Thereby, the user can grasp that the time has come to replacethe contact point.

Second Embodiment

Next, a robot apparatus according to a second embodiment of the presentinvention will be described. FIG. 6 is a block diagram illustrating anintegrated controlling apparatus, a hand and a tool of the robotapparatus according to the second embodiment of the present invention.The configuration of the robot apparatus in the second embodiment isdifferent from that in the first embodiment in the point that the robotapparatus in the second embodiment has a current detecting circuit 450therein, but except for the point, is similar to the configuration inthe first embodiment. Therefore, in the second embodiment, theconfigurations similar to those in the first embodiment are designatedby the same reference numerals, and the description will be omitted.

The robot apparatus of the second embodiment has further the currentdetecting circuit 450 which functions as a current detecting unit thatdetects an electric current which passes through the contact point 423of the hand side contact unit 420.

Here, the electric current which passes through the contact point 423 isthe same as an electric current which passes the power source wire 443,the contact point 523 of the tool side contact unit 520, and the powersource wire 543. Furthermore, also through the power source wire, thecontact point, the contact point and the power source wire all in theground side, which form a return path of the direct current, theelectric current flows which is almost same as the electric current thatpasses through the outward path of the direct current, specifically, theelectric current which passes through the contact point 423.

Accordingly, in the second embodiment, the current detecting circuit 450is provided in the power source wire 443 so as to easily detect theelectric current and also easily transmit a detection result to thecontrolling circuit 101, and is configured to detect the electriccurrent which passes through the power source wire 443. In other words,in the second embodiment, the hand 400A has the current detectingcircuit 450. This current detecting circuit 450 may be provided in thepower source wire 444 therein.

Incidentally, the tool 500 may have the current detecting circuit 450therein. In this case, the current detecting circuit 450 may detect anelectric current which passes through the power source wire 543 or thepower source wire 544. In addition, the current detecting circuit 450may be provided in between the power source circuit 103 and the powerswitch circuit 433. In this case, the integrated controlling apparatus100 may have the current detecting circuit 450 therein.

Information on the electric current (signal which shows the value ofelectric current) which has been detected by the current detectingcircuit 450 is output to the controlling circuit 101 of the integratedcontrolling apparatus 100, through the hand controlling apparatus 431.

FIG. 7 is a flow chart which is used when the contact state between thecontact points is determined, in the robot apparatus according to thesecond embodiment of the present invention. In FIG. 7, the contact stateamong the contact points is determined at the time of the initializationwhich is performed after the hand 400A has acquired the tool 500. Thesteps S41 to S44 and the step S47 are the same as the steps S11 to S14and the step S21 in FIG. 3, and accordingly the description will beomitted.

When the tool 500 is initialized, the position of the claws 502 arealigned with that of the motor 503, but the position alignment isperformed by a current control of the motor 503. After a buttingoperation of the claws 502 has been completed, the controlling circuit101 determines the contact states between the contact points 423 and 424and the contact points 523 and 524, by using the values of the voltageswhich have been detected by the voltage detecting circuit 435 and 535,and the value of the electric current which has been detected by thecurrent detecting circuit 450 (S45).

The controlling circuit 101 issues an alert to the user, when havingdetermined that the contact state is NG in the step S45 (S48).Specifically, the controlling circuit 101 makes the monitor 104 displayan image thereon which shows the alert. Incidentally, the annunciationunit which sends the notice to the user is determined to be the monitor104, but is not limited to the monitor. The annunciation unit may be anunillustrated loudspeaker, for instance, and may make the loudspeakeroutput a sound which shows the alert.

When the controlling circuit 101 has determined that the contact stateis OK in the step S45, or has issued the alert in the step S48, anacquisition of the tool 500 is completed (S46).

When determining the contact state in the step S45, the controllingcircuit 101 determines an electric resistance value, from the differencevalue between the value of the voltage which has been detected by thevoltage detecting circuit 435 and the value of the voltage which hasbeen detected by the voltage detecting circuit 535, and the value of theelectric current which has been detected by the current detectingcircuit 450.

The difference value between the voltages is values of voltages whichhave dropped in between the contact points 423 and 424 and the contactpoint 523 and 524. Accordingly, an electric resistance value, in otherwords, a contact resistance value, can be determined from Ohm's law, byusing the difference value between the voltages and the value of theelectric current. Then, the controlling circuit 101 determines whetheror not the contact resistance value has exceeded the threshold value(threshold value of resistance) which has been set beforehand. If thecontact resistance value exceeds the threshold value, the contact stateis NG, and if the contact resistance value does not exceed the thresholdvalue, the contact state is OK. Here, the threshold value is a valuewhich is stored beforehand in the memory 102 in FIG. 6.

FIG. 8 is a schematic diagram illustrating a relation between an elapsedtime and the value of the contact resistance. As is illustrated in FIG.8, the contact points in each of the contact units 420 and 520deteriorate with the passage of time if being not maintained, and thevalue of the contact resistance between the contact points increases.Accordingly, the controlling circuit 101 determines the contactresistance value by using the difference value that the value of thevoltage which has been detected by the voltage detecting circuit 535 hasbeen subtracted from the value of the voltage which has been detected bythe voltage detecting circuit 435, and the current value which has beendetected by the current detecting circuit 450. Then, the controllingcircuit 101 determines whether or not the value of the contactresistance has exceeded the threshold value (threshold value ofresistance). Here, in FIG. 8, in addition to the threshold value, alimit value is illustrated which is larger than the threshold value. Thelimit value is a value at which the tool becomes incapable of receivingthe electric power or the signal, and the threshold value is preferablyset at a value lower than the limit value.

If the contact point resistance value exceeds the limit value, the hand400A and the tool 500 cannot mutually communicate. The hand controllingapparatus 431 of the hand 400A transmits a signal which shows an errorto the controlling circuit 101 of the integrated controlling apparatus100, and the controlling circuit 101 makes the robot 200 stop theoperation.

Even if the contact point resistance value exceeds the threshold value,the hand 400A and the tool 500 can communicate mutually as long as thecontact point resistance does not exceed the limit value. Accordingly,the controlling circuit 101 can acquire the voltage information from thevoltage detecting circuit 535, and can compute the contact resistancevalue. In this case, the robot 200 is not stopped immediately, and thecontrolling circuit 101 issues the alert to urge the user to performmaintenance or replacement of the contact point at arbitrary timing forthe user.

In other words, when the value of the contact resistance has exceededthe threshold value, the controlling circuit 101 only issues the alertfor calling such an attention that the user needs to maintain thecontact points, for instance, by cleaning and the like (S48), and doesnot make the robot 200 stop the operation. However, in the case of NG inthe step S44, the tool cannot receive the signal, and accordingly thecontact resistance value must exceed the limit value. Accordingly, thecontrolling circuit 101 issues the alert which shows an error in thestep S47, and also makes the robot 200 (refer to FIG. 1) stop theoperation.

The robot apparatus according to the second embodiment determines thecontact resistance value by using the current value which has beendetected by the current detecting circuit 450, then determines whetheror not this contact resistance value exceeds the threshold value, andaccordingly can determine the contact states between the contact points423 and 424 and the contact points 523 and 524 with higher accuracy thanthat in the first embodiment.

The robot apparatus according to the second embodiment can determine thecontact state of the contact point without a work. In addition, therobot apparatus can determine the contact state of the contact point atthe same time when initializing the tool 500.

FIG. 9A is a graph illustrating the relation between the number of toolacquiring times by the hand and a value of the contact resistance. FIG.9B is a graph in which a part of sections in FIG. 9A is expanded.

The values of the contact resistance between the contact points, whichare plotted in FIG. 9A and FIG. 9B, are the maximum values obtained forevery 1000 times of the tool acquiring times. In addition, themaintenance of wiping the surfaces of the contact points in each of thecontact units 420 and 520 has been performed on every rhombic mark inFIG. 9A and FIG. 9B. The cycle of the maintenance has been set at oncein every 40,000 times to 300,000 times.

As is illustrated in FIG. 9A, when the deterioration of the contactpoint progresses, the interval between the tool acquiring times at thetime when the maintenance has been performed and the tool acquiringtimes at which the contact resistance value exceeds the threshold valuebecomes short. In FIG. 9B, the interval is shortened from 23,000 timesto 89,000 times.

There are following two factors which shorten the interval. The firstfactor is a phenomenon that a plated film (of gold, nickel, rhodium orthe like) on the surface of the contact point is peeled, thereby thebase material (iron, copper or the like) is exposed, and the basematerial is oxidized. The second factor is a phenomenon that the surfaceof the contact point is deformed and cannot fully secure the contactarea. Because of these factors, a deterioration occurs which cannot beavoided by the maintenance of wiping the contact point, and accordinglya replacement of the contact points, specifically, a replacement of thecontact units 420 and 520 becomes necessary.

In the second embodiment, the integrated controlling apparatus 100 hasthe counter 105 which counts the number of times the hand 400A hasacquired the tool 500, specifically, the number of times the tool device510 has been mounted on the hand device 410. The counted value by thecounter 105 is reset when a user has performed maintenance.

A threshold value (threshold value for count, for instance, 30,000times) is set beforehand so that the integrated controlling apparatus100 distinguishes whether or not the deterioration of the contact pointcan be restored by the maintenance. In other words, the threshold valuefor the count is stored in the memory 102 beforehand. The controllingcircuit 101 determines whether or not the counted value by the counter105 at the time when the contact resistance value has exceeded thethreshold value is smaller than the threshold value for the count. Then,when having determined that the counted value is smaller than thethreshold value for the count (for instance, 30,000>23,000 times), thecontrolling circuit 101 makes the monitor 104 display the image showingthe notice thereon. Thereby, the user can grasp that the time has cometo replace the contact point.

Third Embodiment

Next, a robot apparatus according to a third embodiment of the presentinvention will be described. Incidentally, the configuration of therobot apparatus is the same as that of the robot apparatus 10 in thefirst embodiment, and accordingly the detailed description will beomitted.

In the second embodiment, the case has been described where the robotapparatus 10 has the current detecting circuit 450. However, in thethird embodiment, the robot apparatus does not detect the electriccurrent, but stores the value of the electric current in the memory 102beforehand. Accordingly, in the third embodiment, the current detectingcircuit 450 can be omitted which has been described in the secondembodiment. The controlling circuit 101 calculates the contactresistance value and determines the contact state similarly to that inthe second embodiment.

The above description will be specifically described below. The memory102 stores the value of the electric current beforehand which passesthrough the contact point 423 in the hand side contact unit 420, whenthe tool 500 (tool device 510) is in a predetermined state.

FIG. 10 is a graph illustrating experimental values of a current valueof a power source, at the time when the tool stops and at the time afterthe tool has completed gripping a work. The current value is 120 [mA]when the tool stops, but is 340 [mA] after the tool has completedgripping the work, where the latter value is about 2.8 times larger thanthe former value. The fluctuations of the current values(maximum-minimum) are each approximately 10 [mA] and are equivalent.Because the fluctuations are equivalent and the latter electric value isabout 2.8 times larger than the former electric value, the resistancebetween the contact points can be measured with higher accuracy.Accordingly, in the third embodiment, the current value which is storedin the memory 102 shall be set at 340 [mA]. The predetermined state inthe third embodiment is specifically a state in which a plurality ofclaws 402 grips the work.

When determining the contact state, the controlling circuit 101 acquiresthe value of the voltage from each of the voltage detecting circuits 435and 535, in the case where a plurality of claws 502 grip the work. Thecontrolling circuit 101 reads out the current value from the memory 102.Then, the controlling circuit 101 computes a contact resistance valueusing these data, similarly to that in the second embodiment. Then, thecontrolling circuit 101 determines whether or not the contact resistancevalue has exceeded the threshold value, similarly to that in the secondembodiment.

As has been described above, the robot apparatus according to the thirdembodiment is configured to use the value which the user has set,specifically, the current value which has been stored in the memory 102,as the current value of the electric current for controlling the motor,and can determine the contact resistance value without the currentdetecting circuit.

The controlling circuit 101 determines whether or not the counted valueby the counter 105 at the time when the contact resistance value hasexceeded the threshold value is smaller than the threshold value for thecount, similarly to that in the second embodiment. Then, when havingdetermined that the counted value is smaller than the threshold valuefor the count, the controlling circuit 101 makes the monitor 104 displaythe image showing the notice thereon. Thereby, the user can grasp thatthe time has come to replace the contact point.

The current value to be stored in the memory 102 may be a current value(for instance, 120 [mA]) at the time when the tool stops, as apredetermined state of the tool 500 (tool device 510). In this case, thecontrolling circuit 101 may acquire the value of the voltage from eachof the voltage detecting circuits 435 and 535, when the tool stops.

Fourth Embodiment

Next, a robot apparatus according to a fourth embodiment of the presentinvention will be described. FIG. 11 is a block diagram illustrating anintegrated controlling apparatus, a hand and a tool of the robotapparatus according to the fourth embodiment of the present invention.In the first to the third embodiments, the case has been described wherethe voltage detecting circuits 435 and 535 detect the voltage in thepower source side, but in the fourth embodiment, the case will bedescribed where the voltage detecting circuits 435 and 535 detect thevoltage in the signal side. Incidentally, in the fourth embodiment, thedescription of the configurations similar to those in the firstembodiment will be omitted below.

A hand 400B has a voltage detecting circuit 435 which is a hand sidevoltage detecting unit, and a tool 500B has a voltage detecting circuit535 which is a tool side voltage detecting unit. In other words, thevoltage detecting circuit 435 is provided in the hand device 410 (referto FIG. 1), and the voltage detecting circuit 535 is provided in thetool device 510 (refer to FIG. 1).

The degree of deterioration with the passage of time of each of thecontact points in each of the contact units 420 and 520 is almost thesame as the others, and accordingly in the fourth embodiment, contactstates of the contact points 421 and 422 in the hand side contact unit420 and the contact points 521 and 522 in the tool side contact unit 520are determined.

Because of this, in the fourth embodiment, the voltage detecting circuit435 detects voltage (potential difference) between the two contactpoints 421 and 422. Specifically, the voltage detecting circuit 435detects the voltage between an arbitrary point (detecting point) of thesignal wire 441 and an arbitrary point (detecting point) of the signalwire 442. Each of the detecting points is preferably close to each ofthe contact points 421 and 422, in consideration of also the voltagedrop due to wiring resistance in each of the signal wires 441 and 442.In the fourth embodiment, the contact point 421 becomes a potential ofthe signal in the positive side, and the contact point 422 becomes apotential of the signal in the negative side; and accordingly, thevoltage detecting circuit 435 detects the voltage of the contact point421 relative to the contact point 422.

The voltage information (signal which shows value of voltage) which hasbeen detected by the voltage detecting circuit 435 is output to thecontrolling circuit 101 of the integrated controlling apparatus 100,through the hand controlling apparatus 431.

The voltage detecting circuit 535 detects voltage (potential difference)between the two contact points 521 and 522. Specifically, the voltagedetecting circuit 535 detects the voltage between an arbitrary point(detecting point) of the signal wire 541 and an arbitrary point(detecting point) of the signal wire 542. Each of the detecting pointsis preferably close to each of the contact points 521 and 522, inconsideration of also the voltage drop due to wiring resistance in eachof the signal wires 541 and 542. In the fourth embodiment, the contactpoint 521 becomes a potential of the signal in the positive side, andthe contact point 522 becomes a potential of the signal in the negativeside; and accordingly, the voltage detecting circuit 535 detects thevoltage of the contact point 521 relative to the contact point 522.

The voltage information (signal which shows value of voltage) which hasbeen detected by the voltage detecting circuit 535 is output to thecontrolling circuit 101 of the integrated controlling apparatus 100,through the tool controlling apparatus 531, the contact points 521 and522, the contact points 421 and 422, and the hand controlling apparatus431.

In the case where the controlling circuit 101 of the integratedcontrolling apparatus 100 acquires the voltage information from thevoltage detecting circuits 435 and 535, firstly, the controlling circuit101 outputs a signal for applying the voltage to the contact points 421and 422 for a fixed period.

Here, the controlling circuit 101 outputs signals of different voltagelevels from each other to the two contact points 421 and 422,respectively. The two signals which the controlling circuit 101 outputsbecome a differential signal. Then, the controlling circuit 101 stopsthe output of the signal, and becomes a state of waiting a signal.

The controlling circuit 101 acquires the value of the voltage which hasbeen detected by the voltage detecting circuit 435, and the value of thevoltage which has been detected by the voltage detecting circuit 535,when being in the state of waiting the signal.

At this time, the controlling circuit 101 acquires the signal whichshows the value of the voltage which has been detected by the voltagedetecting circuit 535, similarly to that in the first embodiment,through the contact points 521 and 522 and the contact points 421 and422.

When determining the contact state, the controlling circuit 101determines whether or not the difference value between the value of thevoltage which has been detected by the voltage detecting circuit 435 andthe value of the voltage which has been detected by the voltagedetecting circuit 535 has exceeded a threshold value which has been setbeforehand, similarly to that in the first embodiment. As has beendescribed above, the robot apparatus according to the fourth embodimentcan determine the contact state of the contact points in the contactunits 420 and 520 even when using the contact points in the signal side,and shows a similar effect to that in the first embodiment.

Incidentally, the robot apparatus has determined the contact state basedon the difference value, in the fourth embodiment, but may compute acontact resistance value by using the current value which has beendetected by the current detecting circuit 450, or the current detectionvalue which has been stored in the memory 102, and determine the contactstate based on the contact resistance value, similarly to that in thesecond embodiment and the third embodiment.

Fifth Embodiment

Next, a robot apparatus according to a fifth embodiment of the presentinvention will be described. FIG. 12 is an explanatory view illustratinga robot apparatus according to the fifth embodiment of the presentinvention. Incidentally, the robot apparatus 10C in the fifth embodimentis a robot apparatus which has an inspection apparatus 700 added to therobot apparatus 10 that has been described in the first embodiment.Other configurations are similar to those in the first embodiment, andaccordingly the description will be omitted.

The inspection apparatus 700 is a biaxial orthogonal robot, and acontact unit 720 in an inspection apparatus side and a maintenance unit730 are provided at a head of a robot (main body of inspectionapparatus) 710.

The robot 710 is structured so that the tool device 510 can be attachedto and detached from the robot 710. The contact unit 720 is connected tothe contact unit 520 by the movement of the robot 710. Specifically, thecontact points of the contact unit 720 come in contact with the contactpoints of the tool side contact unit 520, when the tool device 510 hasbeen mounted on the robot 710. An electric power and a signal aresupplied to the contact unit 720 from the integrated controllingapparatus 100, through an inspection wiring 203 which passes through theinside of the robot 710. Accordingly, the controlling circuit 101 isenabled to supply the electric power and the signal to the tool 500after the contact units 520 and 720 have been connected to each other,and to control the tool 500.

In the fifth embodiment, the inspection apparatus 700 has functions(hand controlling apparatus 431, voltage detecting circuit 435, powerswitch circuit 433, signal switch circuit 436 and the like) which thehand 400 that has been described in the first embodiment has.

After the contact units 520 and 720 have been connected to each other,the controlling circuit 101 determines the connected state of thecontact point in a similar method to that in the first embodiment.Specifically, when the tool device 510 has been mounted on the robot710, the controlling circuit 101 determines the contact state betweenthe contact points in the contact unit 720 and the contact points in thecontact unit 520, by using the value of the voltage that has beendetected by the voltage detecting circuit 535 which is the tool sidevoltage detecting unit.

In the case where the result of having determined the contact state ofthe contact points is NG, the controlling circuit 101 makes the robot710 operate to connect the maintenance unit 730 to the tool side contactunit 520, and makes the maintenance unit 730 maintain the tool sidecontact unit 520. The maintenance means an operation of wiping thesurface of the contact points, and the like.

In the fifth embodiment, the robot apparatus can also make a worksupplying apparatus (unillustrated) supply a work to the tool 500, andmakes the tool 500 grip the work beforehand.

As has been described above, the robot apparatus according to the fifthembodiment can perform the inspection of the tool 500, the maintenanceof the tool 500 and the like, in the time period in which the tool isnot gripped by the robot 200 that is structured by the arm 300 and thehand 400 which actually operate. Thereby, the robot apparatus canenhance an operation efficiency of the whole apparatus.

In the fifth embodiment, the case has been described so as to correspondto the first embodiment where the voltage detecting circuits detect thevoltage values in the power source side, the controlling circuit 101determines the difference value between the voltages, and determines thecontact state by using the difference value between the voltages, butthe present invention is not limited to the case. In similar ways tothose in the second to fourth embodiments, the controlling circuit 101may determine the contact resistance value between the contact points inthe power source side, and may determine the contact state; maydetermine the contact state based on the difference value betweenvoltages of the contact points in the signal side; or may determine thestate of the contact points based on the contact resistance valuebetween the contact points in the signal side.

The present invention is not limited to the above described embodiments,but can be modified in many ways in a range of the technical concept ofthe present invention. In regard to the effects which have beendescribed in the embodiments of the present invention, the most suitableeffects that are created by the present invention are merely enumerated,and the effects according to the present invention is not limited to theeffects which have been described in the embodiments of the presentinvention.

In the first to the fifth embodiments, the case has been described wherethe robot apparatus is configured so that the voltage detecting circuit435 detects the voltage in the hand side or the inspection apparatusside, but the present inventions is not limited to the case. When thevoltage drop can be neglected in the hand side or the inspectionapparatus side, the voltage detecting circuit 435 may be omitted in thehand side or the inspection apparatus side. In this case, thecontrolling circuit may determine whether or not the value of thevoltage which has been detected only by the voltage detecting circuit535 in the tool side has exceeded the threshold value, or may store thevalue of the voltage in the hand side or the inspection apparatus sidein the memory unit beforehand, calculate a difference value or a contactresistance value by using this stored value, and determine whether ornot the difference value or the contact resistance value has exceededthe threshold value.

In addition, in the first embodiment, the case has been described whereeach of the contact units 420 and 520 has the contact points 424 and 524set at the ground, but the present invention can also be applied to thecase where cases of the hand 400 and the tool 500 are set at the ground.In this case, the voltage detecting circuit 435 may detect a voltage(that is, potential) of the contact point 423 relative to the ground(case), and the voltage detecting circuit 535 may detect a voltage (thatis, potential) of the contact point 523 relative to the ground (case).In this case, the controlling circuit results in determining theconnected state between the contact point 423 and the contact point 523.The similar configuration may be applied to the second to the fifthembodiments. In the fourth embodiment in particular, the type of signalis a differential signal, and accordingly the controlling circuit hasdetermined the connected states between the two contact points 421 and422 and the two contact points 521 and 522, but the controlling circuitmay determine either one, for instance, the connected state between thecontact point 421 and the contact point 521.

In addition, in the first to the fifth embodiments, the case has beendescribed where the signal is the differential signal, but even thoughthe signal is a single end signal, the present invention is applicable.In the case of the single end signal in the fourth embodiment, inparticular, the voltage detecting circuits 435 and 535 may detect thevoltage between a contact point (for instance, contact point 421 or 521)in the signal side and a contact point (for instance, contact point 424or 524) in the ground side. Alternatively, when the case is set at theground, the voltage detecting circuits 435 and 535 may detect thevoltage (that is, potential) between the contact point in the signalside and the ground.

In addition, in the first to the fifth embodiments, the case has beendescribed where the controlling unit is the controlling circuit 101 ofthe integrated controlling apparatus 100, but the present invention isnot limited to the case. The controlling unit may be, for instance, thehand controlling apparatus 431 of the hand 400 (in the case ofinspection apparatus 700, controlling apparatus of inspection apparatus700). Incidentally, the case has been described where the handcontrolling apparatus 431 is arranged in the inside of the hand device410, but the hand controlling apparatus may be provided in the outsideof the hand device 410, for instance, in the arm 300 side, in theintegrated controlling apparatus 100 side, or in a different body fromthe above described sides. Concerning also the inspection apparatus 700,the above description is similar. Furthermore, concerning also thevoltage detecting circuit 435 in the hand side, the above description issimilar.

In addition, in the first to the fifth embodiments, the case has beendescribed where the voltage detecting circuit 535 in the tool sidetransmits the signal which shows the value of the voltage that thevoltage detecting circuit 535 has detected, to the controlling circuit101 of the integrated controlling apparatus 100 through a signal wire,what is called, the case where cable communication is performed, but thepresent invention is not limited to the case. In the case where the tool500 and the integrated controlling apparatus 100 have a radiocommunication equipment installed therein, the voltage detecting circuit535 may transmit the signal which shows the value of the voltage thatthe voltage detecting circuit 535 has detected, to the controllingcircuit 101 of the integrated controlling apparatus 100, throughwireless communication.

In addition, in the first to the fifth embodiments, the case has beendescribed where the arm 300 is the vertical multi-joint robot arm, butthe present invention is not limited to the case. The arm to which thehand is attached may be various robot arms, such as a horizontalmulti-joint robot arm, a parallel link robot arm and an orthogonalrobot, for instance.

In addition, in the first to the fifth embodiments, the case where therobot apparatus has one unit of the robot 200 and one unit of the tool500, but the present invention is not limited to the case, and the robotapparatus may have a plurality of robots 200 and/or a plurality of tools500.

In addition, in the first, the second, the third and the fifthembodiments, the case has been described where the robot apparatusdetermines the contact state of the contact points in the power sourceside, and in the fourth embodiment, the case has been described wherethe robot apparatus determines the contact state of the contact pointsin the signal side. However, the present invention is not limited to thecase, and the robot apparatus may determine the contact states of thecontact points both in the power source side and in the signal side.

Other Embodiments

Embodiment(s) of the present invention can also be realized by acomputer of a system or apparatus that reads out and executes computerexecutable instructions (e.g., one or more programs) recorded on astorage medium (which may also be referred to more fully as a‘non-transitory computer-readable storage medium’) to perform thefunctions of one or more of the above-described embodiment(s) and/orthat includes one or more circuits (e.g., application specificintegrated circuit (ASIC)) for performing the functions of one or moreof the above-described embodiment(s), and by a method performed by thecomputer of the system or apparatus by, for example, reading out andexecuting the computer executable instructions from the storage mediumto perform the functions of one or more of the above-describedembodiment(s) and/or controlling the one or more circuits to perform thefunctions of one or more of the above-described embodiment(s). Thecomputer may comprise one or more processors (e.g., central processingunit (CPU), micro processing unit (MPU)) and may include a network ofseparate computers or separate processors to read out and execute thecomputer executable instructions. The computer executable instructionsmay be provided to the computer, for example, from a network or thestorage medium. The storage medium may include, for example, one or moreof a hard disk, a random-access memory (RAM), a read only memory (ROM),a storage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2015-036691, filed Feb. 26, 2015, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A robot apparatus comprising: a robot; a robotside contact point which is provided in the robot and to which a voltageis applied; a tool device which can be attached to and detached from therobot; a tool side contact point which is provided in the tool device,and comes in contact with the robot side contact point as the tooldevice is mounted on the robot; a tool side detecting unit which isprovided in the tool device, and detects an electric output of the toolside contact point; and a robot side detecting unit which detects anelectric output of the robot side contact point, wherein a controllingunit determines a contact state between the robot side contact point andthe tool side contact point, based on a relative value between a valueof the electric output detected by the robot side detecting unit and avalue of the electric output detected by the tool side detecting unit.2. The robot apparatus according to claim 1, wherein the robot has arobot arm and a hand device, and wherein the robot side contact point isprovided in the hand device.
 3. The robot apparatus according to claim2, wherein: the electric output detected by the robot side detectingunit is a voltage or a current of the robot side contact point, and theelectric output detected by the tool side detecting unit is a voltage ora current of the tool side contact point.
 4. The robot apparatusaccording to claim 3, wherein the controlling unit acquires, through therobot side contact point and the tool side contact point, the value ofthe voltage or the current that has been detected by the tool sidedetecting unit.
 5. The robot apparatus according to claim 3, wherein therelative value is a difference value between the electric outputdetected by the robot side detecting unit and the electric outputdetected by the tool side detecting unit.
 6. The robot apparatusaccording to claim 5, wherein the controlling unit determines thecontact state between the robot side contact point and the tool sidecontact point based on a condition as to whether or not the differencevalue has exceeded a predetermined threshold.
 7. The robot apparatusaccording to claim 5, wherein the controlling unit determines thecontact state between the robot side contact point and the tool sidecontact point by using the difference value and the value of the currentwhich has been detected by the robot side detecting unit or the toolside detecting unit.
 8. The robot apparatus according to claim 7,wherein the controlling unit determines the contact state between therobot side contact point and the tool side contact point based on acondition as to whether or not an electric resistance value that isbased on the difference value and the value of the electric currentwhich has been detected by the robot side detecting unit or the toolside detecting unit has exceeded a predetermined threshold value.
 9. Therobot apparatus according to claim 2, further comprising a power sourceunit which applies a direct-current voltage to the robot side contactpoint.
 10. The robot apparatus according to claim 9, comprising two ofthe robot side contact points and two of the tool side contact points,wherein the power source unit applies a direct-current voltage betweenthe two robot side contact points, and the tool side detecting unitdetects a voltage or a current between the two tool side contact points.11. The robot apparatus according to claim 2, wherein the tool devicecomprises a base unit, a plurality of claws that is supported by thebase unit, and can grip or release a grip of a work, and an electricmotor which drives the plurality of claws, and the robot apparatusfurther comprising: a power source unit which applies a direct-currentvoltage to the robot side contact point and supplies an electric powerto the electric motor; and a memory unit which stores a value of anelectric current beforehand that passes through the robot side contactpoint when the tool device is in a predetermined state, wherein whendetermining the contact state, in a case of the predetermined state, thecontrolling unit determines whether or not an electric resistance valuethat is based on a difference value between the value of a voltage whichhas been detected by the robot side detecting unit and the value of thevoltage which has been detected by the tool side detecting unit and onthe value of the electric current which has been stored by the memoryunit has exceeded a threshold value.
 12. The robot apparatus accordingto claim 2, further comprising: a robot side signal contact point whichis provided in the robot device and constitutes a transmission path of asignal; and a tool side signal contact point which is provided in thetool device, and comes in contact with the robot side signal contactpoint when the tool device has been mounted on the robot device; whereinthe controlling unit acquires the signal which shows a value of thevoltage which has been detected by the tool side detecting unit, throughthe tool side signal contact point and the robot side signal contactpoint.
 13. The robot apparatus according to claim 12, further comprisinga tool controlling unit which is provided in the tool device andcontrols an operation of the tool device in response to an input of anoperation signal, wherein the controlling unit outputs the operationsignal to the tool controlling unit, through the robot side signalcontact point and the tool side signal contact point.
 14. The robotapparatus according to claim 2, wherein the controlling unit outputs asignal for applying a voltage to the robot side contact point.
 15. Therobot apparatus according to claim 14, comprising two of the robot sidecontact points and two of the tool side contact points, wherein thecontrolling unit outputs signals of different voltage levels from eachother, to the two robot side contact points, respectively, and the toolside detecting unit detects a voltage between the two tool side contactpoints.
 16. The robot apparatus according to claim 14, wherein twosignals which the controlling unit outputs are differential signals. 17.A controlling method of a robot apparatus comprising a robot, a robotside contact point which is provided in the robot and to which a voltageis applied, a tool device which can be attached to and detached from therobot, a tool side contact point which is provided in the tool deviceand comes in contact with the robot side contact point as the tooldevice is mounted on the robot, a tool side detecting unit which isprovided in the tool device and detects an electric output of the toolside contact point, a robot side detecting unit which detects anelectric output of the robot side contact point, and a controlling unitwhich is electrically connected to the robot, the method comprising:detecting, by the robot side detecting unit, an electric output of therobot side contact point; detecting, by the tool side detecting unit, anelectric output of the tool side contact point; and determining, by thecontrolling unit, a contact state between the robot side contact pointand the tool side contact point based on a relative value between avalue of the electric output detected by the robot side detecting unitand a value of the electric output detected by the tool side detectingunit.
 18. A non-transitory computer-readable recording medium storing areadable program for operating a computer to execute a controllingmethod of a robot apparatus comprising a robot, a robot side contactpoint which is provided in the robot and to which a voltage is applied,a tool device which can be attached to and detached from the robot, atool side contact point which is provided in the tool device and comesin contact with the robot side contact point as the tool device ismounted on the robot, a tool side detecting unit which is provided inthe tool device and detects an electric output of the tool side contactpoint, a robot side detecting unit which detects an electric output ofthe robot side contact point, and a controlling unit which iselectrically connected to the robot, the program comprising code toexecute: detecting, by the robot side detecting unit, an electric outputof the robot side contact point; detecting, by the tool side detectingunit, an electric output of the tool side contact point; anddetermining, by the controlling unit, a contact state between the robotside contact point and the tool side contact point based on a relativevalue between a value of the electric output detected by the robot sidedetecting unit and a value of the electric output detected by the toolside detecting unit.
 19. A control unit configured to control a robotapparatus comprising a robot, a robot side contact point which isprovided in the robot and to which a voltage is applied, a tool devicewhich can be attached to and detached from the robot, a tool sidecontact point which is provided in the tool device and comes in contactwith the robot side contact point as the tool device is mounted on therobot, a tool side detecting unit which is provided in the tool deviceand detects an electric output of the tool side contact point, and arobot side detecting unit which detects an electric output of the robotside contact point, comprising: at least one processor; and at least onememory storing code that, when executed by the at least one processor,performs: acquiring an electric output of the robot side contact pointdetected by the robot side detecting unit; acquiring an electric outputof the tool side contact point detected by the tool side detecting unit;and determining a contact state between the robot side contact point andthe tool side contact point, based on a relative value between a valueof the electric output detected by the robot side detecting unit and avalue of the electric output detected by the tool side detecting unit.